论文部分内容阅读
超高速碰撞后在纯铁靶板材料弹坑底部形成了超细晶结构。通过光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)对弹坑截面不同深度处的微观组织进行观察分析,得到由塑性变形引起晶粒细化的结论。首先,低能量位错结构(LEDS),如高密度位错墙(DDWs)和位错缠结(DTs)的形成将原始晶粒分割为交错的层状结构;随着应变的增大,DDWs和DTs演化为具有低取向差的亚晶界并将层状结构分割为细小胞状结构;亚晶界转变为高角度晶界,最终导致超细晶的形成。对动态再结晶过程中,由冲击波作用下产生的高应变和高应变率导致的超细晶的形成进行了讨论。
Ultra-high-speed collision in the pure iron target material crater at the bottom of the formation of ultra-fine crystal structure. The microstructure of the crater at different depths was observed and analyzed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results of the grain refinement caused by plastic deformation were obtained. First, the formation of low-energy dislocation structures (LEDS), such as high-density dislocation walls (DDWs) and dislocation entanglements (DTs), separates the original grains into staggered lamellar structures. As the strain increases, DDWs And DTs evolve into subgrain boundaries with poor low orientation and segregate the layered structure into finely cellular structures; the subgrain transforms into high angle grain boundaries, eventually leading to the formation of ultrafine grains. In the dynamic recrystallization process, the formation of ultrafine crystals caused by the high strain and high strain rates induced by shock waves is discussed.